RLC ckt's underdamped response

[barneygumble742]

hi...

how can i get A cos (omega t) + B sin (omega t)

into this form: C cos (omega t + theta) ?

does it equal to A+B cos (omega t - 90) ?

i know it has to do with the underdamped response of an RLC circuit. i
was looking into phasors as well.

any help would be greatly appreciated.

mark

 

[quasar987]

I do not think you can friend.

 

[berkeman]

If A=B and C=2A, I think you can get it to work. But not in the general case where the amplitudes of the sin and cos components are different.